Stretch marks can't be prevented by products alone. They will be 5 % effective while 50% can be blamed on genetics and the other on diet and hormones.
Entering your pregnancy with balanced hormones is a good start. I did a cleanse with DIM to rid myself of excess estrogen that builds up in women over time. Excess estrogen in pregnancy can affect the bodies ability to produce other hormones important in pregnancy (like progesterone).
Second nutrition is very very important. Modern diets are high in carbs (empty calories), low in good fats, high in vegetable oils and fiber, low in quality meat. The problem is that eating that way you won't get enough of the nutrients needed to prevent stretch marks.
Important for preventing stretch marks are:
-Zinc and Vitamin C for adequate tissue repair
-Balance of Omega 3/6 fatty acids. Diets these days are higher in Omega 6. I avoid all oils like corn, soy, canola, sunflower and instead eat coconut oil, (real, grasfed) butter (like kerrygold), virgin olive oil, palm oil.
Vitamin E
Gelatin or Collagen, can be obtained from bone broth, adding gelatin to foods, jello (home made, natural)
Liver, I ingest small amounts of liver through home made liver pills. Little cuts of liver are frozen and stored, take a few a week like any other supplement.
As far as hygiene goes - no soap, cleansing with water is enough. I have a mild organic bar soap here for other body parts. I use coconut oil for moisturizing, which delivers moisture far better than cream could. I don't even use skin creams for the face or body because it works so well.
These articles seems to talk about what I wrote, haven't read them fully but maybe they have some more info you'd like to read.
https://paleofitnessmama.com/how-to-not-get-stretch-marks/
https://cavegirlplusone.com/blog?offset=1375900424668
Worth it!!!
I used bio oil through my first pregnancy and got stretch marks around 36 weeks! 
